In the field of drug discovery, there are cases where influences of drugs administered to samples such as cells are evaluated by measuring light emitted from the cells. Patent Literature 1 discloses a measurement device comprising an electrode array for generating an electric field in an observation region within a well for a multiwell plate in which a plurality of wells for placing cells therein are arranged. The electrode array is constituted by negative and positive electrodes which are two parallel plate electrodes. Patent Literature 2 discloses a measurement device which monitors a biological response to electric field stimulation of a cell by detecting fluorescence, while this measurement device employs a structure which can place an electrode pair in the form of a coaxial cable constituted by positive and negative electrodes in a well arranged with a cell.